Refrigeration apparatus



Nov. 5, 1935. c. o. BERGSTROM REFRI GERATION APPARATUS 3 Sheets-Sheet 1 Filed sePt- 1934 a M w v w 5 &) 6 G O 4 Q iw V I J E m m. w

Nov. 5, 1935' c. o, BERGSTROM 2,020,096

REFRIGERAT ION APPARATUS Filed Sept. 5, 1954 3 Sheets-Sheet 2 I 71 pe 11501 CAKL O. BEEGSTeOM y W J m.

Nov. 5, 1935. c. o. BERGSTROM 2,020,096

REFRIGERATION APPARATUS Filed Sept. 5, 1934 v 3 Sheets-Sheet 3 Patented Nov. 5, 1935 A UNITED STATES PATENT @EMQE 2,020,096 REFRIGERATION APPARATUS Carl Oscar Bergstrom, Hyde Park, Mass., assignor to B. it. Sturtevant Company, Inc., Boston, Mass.

' Application September 5, 1934, Serial No. 742,754

9 Claims. (01. 230-190) This invention relates to refrigeration apparan object o e nv ntion s to decrease the tus, and relates more particularly to refrigerant o s o op at n of a e a t Compressor. compressors of a type particularly suitable for Another object of the invention is to provide domestic refrigerators, a simple, inexpensive unloading device for a rey Although the refrigerant compressors used in ge ant compressor.

household refrigerators have been improved Another o j o e nv n on s to ut li e greatly in the past few years, most of those genoil carried with the refrigerant through the reerally used are still too noisy, are too complicated, rie at n y l to lu r at a n f t anand so constructed as to require frequent servparatus.

1o icing and replacements. Desirable features in Another object of the invention is to p v d 10 a household compressor unit are that the driving a valve structure for the refrigerant compressor, motor should not be compelled to start under which is capable of continuous trou -f opfull load; that adequate and automatic lubricaatio tion be provided; that it be very quiet in opera- Another object of the invention is to provide .15 tion; that it be suspended so as to transmit no a simple spring structure f r t pp of and 16 50 suction stroke of the piston.

vibrations to the cabinet within which it is susthe observation of any vibrati ns e p by the pended, and that it operate satisfactorily over operation of refrige n pparatus.

a long period of time without necessity for serv- Another object of the invention is to provide a icing. refrigerant compressor capable of quiet, trouble- 20 According to a feature of this invention, there free operation, which will operate with minimum is mounted within the piston of a refrigerant xpe s m x m m ifi y, nd W h nec compressor a simple spring-operated unloadsity for frequent servicing.

ing device, which holds the suction valve to Other objects of the invention will be apparent the compressor cylinder open until substanfrom t e f low ng descr ption taken with the tial pressure has developed beyond the valve drawing of which! 5 to then close same, thus permitting the driving Fig. 1 is a plan vi w, looking d wnward y up n motor to attain substantial speed before pickan as em led Compressor unit according to this ing up its full load. It has previously been invention; proposed to use unloading devices with com- Fig. 2 is an end view looking w s the mpressors, but those devices previously proposed D s e o Fi'g- 30 have been much more complicated and expensive Fig. 3 is an enlarged vertical sectional view than the simple one according to this invention. through the compressor and through the bearings According to another feature of this invention, of the motor; a muffler is provided in the cylinder head of the Fig. 4 i e sectional V w 131mg the lines compressor to silence the noise caused ordinarily of Fig.

. 36 by the pulsation in the vapor pressure. Fig. 5 is a sectional view along the hnes 5-5 According to another feature of this invention, of Fig. lubrication difficulties are minimized by utilizing Fig. 6 is a plan view looking downwardly on ball bearings for the main bearings, .and by prothe muffler adapted to be mounted in the cylinder 40 viding forced feed lubrication for all of the other head, as shown by Fig. 5. A portion of two of bearings with oil circulating with the vapor the muilier plates is removed to show the spacing through the apparatus. of the openings provided for the passage of the According to another feature of this invencompressed vapor; tion, the tendency of the suction valve to stick Fig. '7 is a plan view, l k n pw y p n open, due to the formation of an oil film on the the outlet valve structure of'Fig. 5; 45 outlet side thereof, is eliminated by providing a ig- 8 is a P w looking downwardly p spring which tends to maintain the suction valve the outlet valve structure of Fig. 5, and closed, but the pressure of which is insuflicient Fig. 9 is a pla V looking p y up to prevent the opening of the valve during the the head of the piston of Fig. 5, and illustrates According to another feature of this invention, head with the "plurality of openings for the the compressor and driving motor are suspended-- passage of the vapor from the piston head. from an u'nderslung base by two simple flat The assembled compressor motor unit is illussprings which. prevent the transmission of vitrated by Figs. 1 and 2. The induction motor 55 brations. l0, which is preferably of the capacitor type, 55

the inlet valve in position withinthe cylinder is bolted to the compressor I by means of the nuts l3 screwed upon the bolts l2. The compressor l l is supported from the base l4 by means of the single leaf spring I5, the two ends of 5 which are attached to the upper portion of the compressor at I6, and the flattened base portion of which is attached to the base M by means of the nuts H on their associated bolts which extend into the base. The motor I0 is likewise supported from the base by means of a similar leaf spring l8, the two ends of which are rotatedly attached at the upper portion of the motor housing at l9 and the flattened base portion of which is attached to the base l4 by the two nuts on their respective bolts which extend into the base.

' This simple spring suspension permits the unit to float freely at its two ends and absorbs all movement of the unit, thus preventing the trans- 20 mission of any vibrations to the base M. The

unit can be quickly and easily placed on or removed from its base and the supports have suflicient strength for' all stresses which may be placed upon them.

The internal mechanism of the compressor will now be described with reference to Figs. 3 to 9, inclusive.

The compressor H is of the single stage type, having but a single piston because of the difficulties of equally loading the pistons of multistage units.

The piston 2| is adapted to be reciprocated by means of its piston rod 24, the lower end of which is rotatably mounted on the shaft 22, which, in

v turn, is rotatably and eccentrically mounted upon the shaft 23, which, in turn, is rotated by the armature of the electric motor. The upper end of the piston rod 24 is rotatably mounted upon the wrist pin 25 of the piston 2|.

The suction valve mechanism is contained within the piston 2|. The piston has a removable head 26 which is'threaded into the upper portion of the piston with threads at. 21. The upper portion of the piston is provided with a 45 central opening 28, through which the vapor passes to be later compressed. Above and communicating with the opening 28, is the larger opening 29, over which the valve 30 seats to close off the flow of vapor. Arranged within the open- 5 ing 29 and in contact with its base and with the piston 30, is the unloading spring 3|, which is provided to prevent the seating of the valve 30 until suflicient pressure has developed on the output side of the valve to overcome the pressure 55 of the spring 3|, thus permitting the valve to become seated against the opposing action of the spring. This permits the motor driving the compressor to attain substantial speed before picking up the full load of compressing the refriger- 60 ant.

The removable head 26 of the piston is provided with a central groove 32, in which is mounted the spring 33. The upper portion of the spring 33 contacts with the upper extremity of (55 the groove 32 and the lower portion of the spring 33 contacts with the upper surface of the valve 30. Spring 32 develops sufllcient pressure to prevent the valve 30 from sticking to the lower portion of the piston head 26. Oil is carried by the vapor 7 passing through the valve and it is diflicult to prevent a thin film of oil from forming on top of valve 30 and often, when the valve was opened and came in contact with the lower portion of the piston head 26, the film of oil caused it to 1. stick to the lower portion of the piston head.

thus causing the valve to remain open during the compression strokes. The spring 33 is incapable, however, of preventing the valve 30 from opening when it should open in its normal operation. 5

During the down stroke of the piston, the vapor passes into the cylinder through the plurality of openings 35, the circumferential arrangement of which is illustrated by Fig. 9. The vapor is then compressed during the up stroke of the pis- 10 ton and then passes through the central opening 36 above the head 26 of the piston and past the outlet valve 31, which is lifted up at the end of the compression stroke to permit the vapor to fiow into the opening 38, which, in the ordinary 15 compressor, is the exhaust port.

Provided above the opening 38 within the and housing or cylinder head 80 of the compressor are the three mufiler discs 39, 40 and 4|. The discs are spaced apart by means of the washers 2o 42 and 43. The lower disc 39 contains the small openings which are out of alignment with openings 44, and'the outer disc 4| is provided with the openings 46 which, again, are out of alignment with the openings 45 in its neighbor- 25 ing disc 46. In operation, the compre:sed vapor leaving the-cylinder of the compressor, tends to expand suddenly in the greater space provided by the discharge outlet and connecting to it. This causes a pronounced noise which the mufller 3o herein described completely dissipates. This is accomplished by having the compressed vapor from the cylinder pass first through the openings 44 in the disc 39, the vapor then expanding to a degree in the space between the discs 39 and 40. 35 The vapor next passes through the openings 45 in the disc 40, and again expands in the space between the discs 40 and 4|. The vapor then passes through the small openings 46 and. expands into the outlet from the compressor. The 4 expansion into the outlet of the compressor thus takes place in several stages, with the result that the noise usually caused by the intermittent compressions and expansions is eliminated.

The compressed vapor, after passing through 45 the final mufller openings 46, passes from the compressor through-the openings 41 and 48.

The outlet'valve 31 is normally restrained from opening, due to the pressure of the three-tongued spring members 50, which press downwardly upon 50 its upper surface and which are formed in a disc of spring metal. Additional discs with springs 50 may be added to adjust the pressure upon the valve 31 (see Figs. '1 and 8). The spring members 50 are centered in the slots 5| of the plate 52.

The muffler and outlet valve mechanism are bolted to the upper portion of the compressor by means of the three screws 53.

By way of example, a refrigerant compressor according to this invention, may contain 18 ounces of methyl chloride and 8 ounces of oil. The oil is carried through the apparatus with the vapor and is used to lubricate certain of the bearings as follows:

The oil and vapor returning from the expansion coils enter the compressor through the inlet port 55 (Fig. 3) and then pass thro ughthe sylphon seal 56 and along the shaft 23 into the channel 51, where it provides lubrication for the contact between the members 58 am 59. The

oil then passes through several radial openings 60 (only one of which is shown) into the central opening 6| of the'shaft 23. Some of-the oil passes out the opening 62 at the end of the shaft and some passes up through the channel 63 to lubricate the bearing between shaft 23 and eccentric cylinder 22, after which the oil passes into the opening 64 in the cylinder 22 and thence through the channel 65 to lubricate the bearing between the piston rod 24 and cylinder 22.

Referring now to Fig. 5, it is seen that the oil carried by the vapor into the interior of the piston 2|, enters the channel 66 in the upper portion of the piston rod 24 and lubrioates the bearing of the wrist pin 25.

The lower portion of the piston rod 24 is provided with a scoop 61 for picking up oil from the oil sump 68 in the lower portion of the compressor. The oil level is maintained just above the end of the scoop Gland tapped plug 69 is provided at the end of the compressor to enable inspections to be made as to the oil level.

-is closed by the The main compressor bearing 10 and motor bearing H are ball bearings, the latter of which may be suitably packed in grease and the former of which is lubricated by slight leakage of oil past the thin metal seals 12, which are provided to prevent the passage of any substantial amount of vapor and oil under pressure through the bearing.

The shaft 23 of the unit is integral throughout the motor and compressor. This is preferred because it eliminates the necessity for shaft couplings and provides stronger construction.

In operation, upon rotation of the shaft 23 by the motor, the oil and vapor within the compressor is drawn by the suction action of the piston through the plained, this valve remains open, due to the action of the spring-3|, until suflicient pressure has developed on the output side of the valve to overcome the action of the spring 3|, thus enabling the motor to develop full speed before takingup its full load.

To prevent any oil film on the upper side of the valve from causing the valve to stick to the lower portion of the piston head 26, the spring 33, which tends to force the valve 30 away from the piston head, is provided.

The valve 30 is opened during its downward stroke by the action of the vacuum created above it, the outlet valve during suction being maintained, of course, closed. During the upward and compression stroke of the piston, the valve 30 pressure developed above it. During the down stroke, valve 30 is open and the vapor drawn in through this valve passes out into the compressor cylinder through the plurality of circumferential openings (Figs. 5 and 9) and enters the space 36 below the outlet valve 31. The outlet valve 31 is normally maintained closed by action of the springs 50, which press downwardly upon its upper surface. During ;operation, the compression developed beneath the valve 31 is suiiicient to overcome the action of the springs 50, causing the valve to open. The compressed gas then enters the space 38 and passes through the staggered small openings in the compressor discs 39,. 40, and 4|, whichhave previously been described, which enable the compressed refrigerant to be sufliciently expanded and so gradually that the noise of discharge which occurs where no muiiier is provided, is overcome. The gas then passes through the space 41 and outlet -into the tubing which is employed to convey the refrigerant to the condenser and the condenser and evaporator coils.

It has been found that the loss in compresion and of e'fliciency of the unit through the use of the mumer is so slight as compared to the adinlet valve 30. As previously exvantagesgained through the quietness of operation, that they are immaterial. It is realized that other forms of silencers, such as a different typeof muflier or acoustic filters may be substituted for the muflier illustrated, by those skilled in 5 the art, after having had access to this disclosure.

Whereas one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the details described, since many modifications may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In refrigerating apparatus, the combination 15 of a compressor cylinder, a cylinder head, a piston movable in said cylinder, a removable head for said piston, and a suction valve located within said piston adjacent said removable head, said .piston having a central opening therein for the 0 intake of fluid during the suction stroke of said piston, and said piston having a pluralityof circumferentially arranged openings for permitting the passage of vapor from said piston into the compression side of said cylinder during the suction stroke of said piston in said cylinder.

2. In refrigerating apparatus, the combination of a compressor cylinder, a head through which compressed vapor is discharged, a piston movable in said cylinder for compressing the 30 vapor, an exhaust valve between the compression side of said piston and the head of said cylinder, and means comprising a silencer between said valve and the head of said cylinder for silencing the noises of the vapor resulting from 35 the action of said piston thereon.

3. In refrigerating apparatus, thecombination of a compressor cylinder, a head through which compressed vapor is discharged, a piston having a compression side and a suction side 40 movable in said cylinder for compressing the vapor, an exhaust'valve between the compression side of said piston and the head of said cylinder, and means comprising a silencer between 5 said valve and the head of said cylinder for silencing the noises of the vapor resulting from the action of said piston thereon.

4. In refrigerating apparatus, the combination of a compressor cylinder, a head through which compressed vapor is discharged, a piston having a compression side and a suction side a movable in said cylinder for indrawing and compressing the vapor, exhaust .valve mechanism, mufller mechanism for muming the noises of the vapor resulting from the action of said piston thereon, and means for securing said valve mechanism and said muiiier mechanism within the compression side of said cylinder between the head thereof and the compression side of said piston. 7

5. In refrigerating apparatus, the combination of a compressor cylinder, a head through which compressed vapor is discharged, a piston having a compression side and a suction side movable in said cylinder for indrawing and compressing the vapor, exhaust valve mechanism, muflier mechanism for mufliing the noises of the vapor resulting from the action of said piston cylinder, a piston movable in said cylinder for compressing a refrigerant vapor and an exhaust valve assembly mounted between the head of said cylinder and the compression side of said piston, said assembly comprising a relatively small disc valve, a relatively large flat spring mounted above said valve with its center above the center of said valve and having a plurality of spring tongues in contact with the outlet side of saidvalve.

'7. In refrigerating apparatus, the combination of a compressor cylinder, a head for said cylinder, 9. piston movable in said cylinder for compressing a refrigerant vapor, and an exhaust valve assembly mounted between the head of said cylinder and the compression side or said piston, said assembly comprising. a relatively small disc valve, a relatively large flat spring mounted above said valve with its center above vthe center of said valve and having a plurality of inwardly directed radial tongues in contact with the outlet side of said valve.

8. In refrigerating apparatus, the combination of a compressor cylinder, a cylinder head, a piston movable in said cylinder, a removable head for said piston, and a suction valve located within saidpiston, adjacent said head for said piston, said piston having a central opening therein connecting with the suction side of said valve and the suction area of said cylinder dur- 5 ing the suction stroke of said piston and said head for said piston having a plurality of circumferentially arranged openings connecting with the discharge side of said valve and the compression side of said cylinder during the compression stroke of said piston.

9. In refrigerating apparatus, the combination of a compressor cylinder, a cylinder head, a piston movable in said cylinder, a removable head ior said piston, and a suction valve located within said piston, adjacent said removable head, said removable head having a central protruding portion of reduced area, means between the compression side of said piston and the head of said cylinder forming an exhaust passage into which said central portion of said removable head extends at the end of the compression stroke of said piston, and an exhaust valve mounted between said passage and head of said cylinder.

CARL OSCAR BERGSTROM. 

